Threonine is an essential amino acid in humans. It is abundant in human plasma, particularly in newborns. Severe deficiency of threonine causes neurological dysfunction and lameness in experimental animals. Threonine is an immunostimulant which promotes the growth of thymus gland.
The Union Pacific Railroad, Building America. The Union Pacific (UP) is one the largest and most powerful railroads in the country. This historic system has been in operation since before the Civil War and much of the general public has at least a general knowledge of UP since it formed the eastern segment of the Transcontinental Railroad.
1 CSX Transportation Inc., operates the largest railroad in the eastern United States with a 22,000-mile rail network linking commercial markets in 23 states, the District of Columbia, and two Canadian provinces.  UP - Union Pacific Railroad. Union Pacific Railroad is an operating subsidiary of Union Pacific Corporation. It is the largest railroad in North America, operating in the western two-thirds of the United States.